In cable control systems comprising a conduit and a core element movable relative to the conduit, it is desirable to be able to adjust the length of the system after it is installed, for example, in an automobile as in a clutch control system, throttle control system, brake control system or pull control system.
Typical adjustment devices are shown, for example. in U.S. Pat. No. 4,378,713, U.S. application Ser. No. 832,526 filed Feb. 21, 1986 abandoned and became co-pending File Wrapper Continuation (F.W.C.) application Ser. No. 07/120,721 filed on Nov. 6, 1987, and U.S. application Ser. No. 917,914 filed Oct. 10, 1986, abandoned and became F.W.C. application Ser. No. 07/131,274 filed on Dec. 9, 1987 now U.S. Pat. No. 4,762,017 issued on Aug. 9, 1988 having a common assignee with the present application.
Among the objectives of the present invention are to provide an automatic adjustable device for cable control systems which can be readily activated after installation of the cable control system to adjust the tension automatically; which will automatically further adjust throughout the life of the cable control system continuously to accommodate changes, which can be readily disassembled, rearmed and reactivated without damaging the device; which is simple; which does not require special tools and which does not require a great deal of training to install or repair.
In accordance with the invention an automatic control device for cable control systems comprises a first member adapted to be fixed, a second member connected to the conduit of a cable control system, and a third member interposed between the first member and the second member. The third member has one-way ratcheting teeth engaging complementary teeth on the first member. A spring is interposed between the third member and the second member. The second member includes circumferentially spaced helical threads that engage complementary grooves in the first member. The second member further includes circumferentially spaced longitudinally extending ribs which engage the grooves of the third member. The device includes a mechanism for locking the parts together against longitudinal movement. When the mechanism is released, the force of the spring urges the second member axially away from the first member and the ratcheting teeth permit the second member to rotate relative to the first member, thereby elongating the conduit relative to a core element that extends through the first member and second member. After adjustment, the one way clutch defined by the ratchet teeth permits relative rotation in one direction only by preventing rotation between the third member and the first member thus preventing axial inward movement between the first member and second member. This retains the adjusted position.